We have continued our work using real-time ultrasound imaging to study various parameters of tongue and oral motion during speech and swallowing. We have established this technique to visualize the soft-tissue structures of the mouth, developed a grid-digitizing system to analyze tongue motion during speech and completed several preliminary studies of tongue and hyoid motion in normals and elderly subjects during swallowing. Over the last year our research has focused on 4 areas: 1) development of a computerized analysis system for measuring tongue curvature and tongue motion variations during production of phonemes, 2) establishing methods for making direct measurements from a video screen rather than from photographs off of a video image as previously reported, 3) determining mathematical models which will characterize tongue motion during speech, and which can be used in our next phase of work on swallowing, and 4) continued application of ultrasound biofeedback in speech training. Using discrete points on the surface of the mid-sagittal section of the tongue, two methods of mathematical analysis were studied for reliability, a) difference approximations, and b) a curve fit. Slope was reliably calculated using different approximations and phonemes which have a point of inflection along the tongue surface were best discussed with a cubic fit. These findings should make clinical research in speech production reproducible in a variety of settings without using invasive or harmful techniques.